Brief Summary

Introduction

The species is widely distributed in Europe and Asia excluding western and southwestern Europe and eastern and southern Asia. Janicki, who worked out the life cycle of the species, suggested that the original life cycle, in the evolutionary past, included a crustacean first and a fish second intermediate host as well as an extinct final host that fed on the fish, harbouring the adult parasite in its digestive tract (Fig. 9). Justification for this hypothesis is that, in other cestodes, stages infecting the body cavity of a fish host are larval forms (plerocercoids). The hypothetical original life cycle would resemble that of Diphyllobothrium latum, which uses crustaceans as first and fish as second intermediate, and fish-eating mammals as final hosts. The maximum length of specimens is 65 mm, the maximum width 30 mm.